This article presents a new ternary-porosity model for evaluating the productivity of horizontal wells in low-permeability gas reservoirs with evenly and unevenly spaced hydraulic fractures. The model accounts for the properties of these fractures. Dimensionless production rate is derived by using the Laplace transform. The effects of hydraulic fractures, natural fractures, and the matrix of the bed on cumulative yield are analyzed systematically. The results show that it is necessary to not only optimize the number of hydraulic fractures and their conductivity but to also include the fracture distribution patterns in the fracture design. The article discusses the parameters that affect the optimum number of hydraulic fractures, including drainage area, the length of the horizontal well, the properties of the natural fractures, matrix permeability, and flow capacity. The model that is derived is rigorous but is also versatile enough for integrating the flow and reservoir characteristics of low-permeability gas reservoirs, and it can be used to optimize the design of hydraulic fracturing.